Increasingly, evidence-based guidelines are available to assist physicians in making decisions about diagnosis and management. However, despite growth in our evidence base, the gap between evidence and practice remains wide, for a multitude of reasons. These include system barriers such as inadequate resources, physician barriers such as lack of knowledge or lack of time, and patient barriers such as misunderstandings or noncompliance. We seek to better understand reasons for these gaps between evidence and practice and to try to overcome these barriers through the use of computer-based decision support. We will focus on the ambulatory setting, where the pace is such that speed of access to decision support is especially critical. Our interventions will occur at the time of the patient visit in the workflow of the physician's practice. We will develop paper- based and electronic guidelines, reminders, and alerts for health maintenance, disease management, medication management, and ancillary test ordering. We will then focus on evaluating the impact of these alerts, reminders, and guidelines on physician compliance with evidence-based recommendations. In addition, we will evaluate the impact of electronic result tracking and follow-up systems on physician compliance with guidelines. Finally, patient, physician, and system barriers to compliance will be assessed in a diverse array of clinical settings. Because our integrated delivery system has a highly developed computer information system and outpatient electronic medical record, we are in an excellent position to implement computer- based interventions in the ambulatory setting. The results of the study will be important because they will accelerate the acceptance and implementation of such computer decision-support systems in other settings.